Nephrotoxicity due to immune checkpoint inhibitors in rural oncology.

Abstract

e15084 Background: Case studies and retrospective chart reviews of health system data have demonstrated an increased risk of nephrotoxicity in patients receiving immune checkpoint inhibitors (CPIs) compared to the incidence of nephrotoxicity reported in clinical trials. The primary objective of this study is to determine the extent to which CPIs may induce nephrotoxicity in a real-world, rural population. The secondary objectives are to identify risk factors for renal dysfunction and describe real-world use of this relatively new class of medications. Methods: This represents a retrospective review of patients receiving at least one dose of a CPI at Marshfield Clinic Health System (MCHS) in Central Wisconsin from May 2013 to November 2019. Baseline serum creatinine, defined as the average of all serum creatinine values obtained within 6 months of the CPI start date, was compared to all serum creatinine measurements during CPI therapy and through 60 days after the last CPI dose. Acute kidney injury (AKI) was defined using the Kidney Disease Improving Global Outcomes definition. Patients developing an AKI of at least three day duration were further assessed to determine the likely cause of AKI. The incidence of potentially CPI-induced AKI was our primary outcome. Chi-square test will be used to compare incidence of AKI among different CPIs. A subdistribution hazard regression will be used to assess the association between the incidence of potentially CPI-induced AKI and patient characteristics (including comorbidities, type of cancer diagnosis, demographics, baseline ECOG score, CPI line in therapy, time lapse between diagnosis and CPI start, and concomitant nephrotoxic medications) while accounting for the competing risk of death. Results: A total of 922 patients received at least one dose of a CPI at MCHS during the study period. After applying exclusion criteria, a total of 920 patients were included in the analysis. The incidence of AKI of any duration and due to any cause was 29.5% (272 of 920 patients). Conclusions: The raw incidence of AKI in our patient population receiving CPIs is higher than previously published studies. However, our data are still being refined and research is in progress.